Project: “Tex-AS”

Development of flow-through textile-based photobioreactors for integrated algae production in shrimp indoor aquaculture systems.

The aim of the project was to develop a flow-through, textile-based photobioreactor for cultivating microalgae. This reactor is intended to be integrated into aquaculture systems to prevent water eutrophication by removing excess nutrients (such as nitrates and phosphates) derived from feed residues and animal waste, while simultaneously converting these nutrients into algal biomass. The resulting biomass can further be used as feed for specific species (such as shrimp).

The goal was to enhance the sustainability of shrimp farming by integrating algae cultivation, which can serve as a renewable food source for the shrimp while simultaneously helping with water quality management in the aquaculture system.

The project focused on the surface functionalization of textiles to immobilize microalgae on textile support structures. The coatings developed for this purpose were required to have strong adhesion and layer stability on textiles. Additionally, the coatings needed to allow for partial growth of the embedded microalgae. Successful Sol-Gel-based coatings were developed to embed microalgae on various textile materials. Both pure SiO₂ coatings and organic/inorganic hybrid coatings were created. Furthermore, modified coatings were developed to improve algae adhesion.

Various textile materials were tested, and it was found that Chlorella vulgaris showed a preferential adhesion to textiles with a positive surface charge. The established microalgal biofilms demonstrated high long-term stability and productivity. Particularly with the use of organic/inorganic hybrid coatings, the biofilms also exhibited excellent stress resistance. This suggests that textile substrates with positive surface charges are highly effective in promoting the attachment and growth of Chlorella vulgaris, while hybrid coatings further enhance the stability and resilience of the biofilms under varying conditions.

Using a specific textile, good biofilm formation of Scenedesmus vacuolatus was observed without any coating. When the initial colonization by S. vacuolatus was low, the textiles were predominantly colonized by diatoms from the system water by the end of the experiment. In contrast, a high initial colonization by S. vacuolatus resulted in a higher proportion of this species, with reduced colonization by diatoms. Additionally, light exposure increased the omega-3 fatty acid content in the algal biofilm.

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ANSPRECHPARTNER:
Dr. Ulrich Soltmann
Fachsektion Dresden – “Funktionelle Schichten”
Tel.: 0351 / 2695 343
E-Mail: soltmann@gmbu.de